According to
http://www.mobipocket.com/dev/articl...e=metadata.htm, there is no metadata entry for series in Mobipocket format. There are only:
eBook Title
Author (Last Name, First Name. Multiple authors are separated by semicolons)
Publisher (not used in the wholesale distribution system, your login identifies you as a publisher)
Imprint (optional)
ISBN
Language
Main Subject
Description
Review
Publishing Date (for reference only)
Cover image (by default, the cover image of the eBook is used; but one can used a different cover image in the eBook and in the wholesale distribution system)
Demo PRC file (optional, demo files can usually be generated automatically by the wholesale distribution system). This has to be an unencrypted Mobipocket PRC file
Suggested retail price and currency (mandatory to deploy to a wholesale distribution system)
Territory restriction